Improve --help output

pacman_mirrors/custom_help_formatter.py

+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# This file is part of pacman-mirrors.
+#
+# pacman-mirrors is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# pacman-mirrors is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with pacman-mirrors.  If not, see <http://www.gnu.org/licenses/>.
+
+import argparse
+
+
+class CustomHelpFormatter(argparse.HelpFormatter):
+    """Provide a customized format for help output.
+    http://stackoverflow.com/questions/9642692/argparse-help-without-duplicate-allcaps
+    https://github.com/Ecogenomics/mingle/blob/master/mingle/custom_help_formatter.py
+    """
+
+    def _split_lines(self, text, width):
+        return text.splitlines()
+
+    def _get_help_string(self, action):
+        """Place default value in help string."""
+        h = action.help
+        if '%(default)' not in action.help:
+            if action.default != '' and action.default != [] and action.default != None and action.default != False:
+                if action.default is not argparse.SUPPRESS:
+                    defaulting_nargs = [argparse.OPTIONAL, argparse.ZERO_OR_MORE]
+
+                    if action.option_strings or action.nargs in defaulting_nargs:
+                        if '\n' in h:
+                            lines = h.splitlines()
+                            lines[0] += ' (default: %(default)s)'
+                            h = '\n'.join(lines)
+                        else:
+                            h += ' (default: %(default)s)'
+            return h
+
+    def _fill_text(self, text, width, indent):
+        """Permit multiple line descriptions."""
+        return ''.join([indent + line for line in text.splitlines(True)])
+
+    def _format_action_invocation(self, action):
+        """Removes duplicate ALLCAPS with positional arguments."""
+        if not action.option_strings:
+            default = self._get_default_metavar_for_positional(action)
+            metavar, = self._metavar_formatter(action, default)(1)
+            return metavar
+
+        else:
+            parts = []
+
+            # if the Optional doesn't take a value, format is:
+            #    -s, --long
+            if action.nargs == 0:
+                parts.extend(action.option_strings)
+
+            # if the Optional takes a value, format is:
+            #    -s ARGS, --long ARGS
+            else:
+                default = self._get_default_metavar_for_optional(action)
+                args_string = self._format_args(action, default)
+                for option_string in action.option_strings:
+                    parts.append(option_string)
+
+                return '%s %s' % (', '.join(parts), args_string)
+
+            return ', '.join(parts)
+
+    def _get_default_metavar_for_optional(self, action):
+        return action.dest.upper()
+
+    def _get_default_metavar_for_positional(self, action):
+        return action.dest

pacman_mirrors/pacman_mirrors.py

@@ -34,6 +34,7 @@ import os
 import importlib.util
 
 from pacman_mirrors_gui import chooseMirrors
+from custom_help_formatter import CustomHelpFormatter
 
 
 def print_write_error(e):
@@ -117,35 +118,42 @@ class PacmanMirrors:
         else:
             gtk_available = True
 
-        parser = argparse.ArgumentParser()
+        parser = argparse.ArgumentParser(formatter_class=CustomHelpFormatter)
         parser.add_argument("-g", "--generate",
-                            help="generate new mirrorlist",
-                            action="store_true")
+                            action="store_true",
+                            help="generate new mirrorlist")
         parser.add_argument("-m", "--method",
-                            help="use generation method",
-                            type=str, choices=["rank", "random"])
+                            type=str,
+                            choices=["rank", "random"],
+                            help="generation method")
         parser.add_argument("-b", "--branch",
-                            help="use branch name",
-                            type=str, choices=["stable", "testing", "unstable"])
+                            type=str,
+                            choices=["stable", "testing", "unstable"],
+                            help="branch name")
         parser.add_argument("-c", "--country",
-                            help="use only mirrors from country[,country,...]",
-                            type=str)
+                            type=str,
+                            help="comma separated list of countries "
+                                 "where mirrors will be used")
         parser.add_argument("-d", "--mirror_dir",
-                            help="use path as mirrorlist directory",
-                            type=str)
+                            type=str,
+                            metavar="PATH",
+                            help="mirrors list path")
         parser.add_argument("-o", "--output",
-                            help="specify output file",
-                            type=str)
+                            type=str,
+                            metavar='FILE',
+                            help="output file")
         parser.add_argument("-t", "--timeout",
-                            help="server maximum waiting time (seconds)",
-                            type=int)
+                            type=int,
+                            metavar="SECONDS",
+                            help="server maximum waiting time")
         if gtk_available:
             parser.add_argument("-i", "--interactive",
-                                help="interactively generate a custom mirrorlist",
-                                action="store_true")
+                                action="store_true",
+                                help="interactively generate a custom "
+                                     "mirrorlist")
         parser.add_argument("-v", "--version",
-                            help="print the pacman-mirrors version",
-                            action="store_true")
+                            action="store_true",
+                            help="print the pacman-mirrors version")
         args = parser.parse_args()
 
         if len(sys.argv) == 1:
@@ -153,7 +161,7 @@ class PacmanMirrors:
             exit(0)
 
         if args.version:
-            print("pacman-mirrors 1.5")
+            print("pacman-mirrors 20150808")
             exit(0)
 
         if args.generate: